.box1{
  width: 200px;
  height: 200px;
  background: url('./assets/a.jpg') no-repeat;
  background-size: 100% 100%;
}
.box2{
  width: 300px;
  height: 300px;
  background: url('./assets//b.jpg') no-repeat;
  background-size: 100% 100%;
}
span{
  display: inline-block;
  width: 16px;
  height: 16px;
  color: #ccc;
}